Explorer’s Log: Moonwort Magic

For the previous entry in the Walker series, see my blog post of 6 April.

During this June excursion to the Walker, Shane and I spent some time crawling and crouched, scanning the roadside ground for moonworts. Strange, elusive little plants that had talismanic power in various traditional cultures. Moonworts still possess their magic, but their lore has faded; hardly anyone is even aware of them today. Moonwort hunting is a favourite of northern North American botanists. If you drive along country lanes or forest service roads, and you see one or more people down on their knees & elbows in meadows or old pastures, peering at the ground, stop and ask if they’re hunting for moonworts.

To the Europeans of hundreds of years ago, moonworts had special authority over metals. There were beliefs that moonworts could un-shoe horses. Alchemists used moonworts to catalyze common metals into rare ones. Moonworts could open locks in lieu of a key. Maybe this was because moonworts are vaguely key-like in appearance. Like this:

Botrychium pinnatum

Moonworts are ferns, and ferns are cryptogams. Cryptogam is an old-fashioned term that sprang up in the days when people still placed all things, at the highest level of classification, into “animal, plant, or mineral”. Looking one level down in classification, early botanists didn’t know what to do with those various unrelated plants and plantish things that have no flowers: mosses, mushrooms, lichens, ferns. When scientific botanical classification was just getting underway, plant classification depended foremostly on numbers of flower parts, Linnaeus’ floral formulas. The flowerless had nowhere to go in this schema. So ferns and the rest had to be swept under the rug of crypto – hidden gamy – sexual union, the cryptogams.

Even earlier European naturalists believed that cryptogams really did have flowers, but those flowers were extremely secretive and ephemeral, unobserved except by the blessed or the lucky or the insane. Ferns were said, by master naturalists, to flower only at midnight during a full moon, on St. John’s Eve, or at other such occult moments. How else could they reproduce?

But now we know that ferns make spores, which in turn make male gametophytes that issue free-range sperm, unlike the pollen-bound sperm of flowering plants. And they also make spores that in turn make female gametophytes to receive their male visitors inconspicuously, in moist dark places. No flowers necessary. And no seed. The mature plants arise direct from the secret union of gametes, direct from the wee and seldom seen female fern gametophyte.

The intriguing cryptosex of those never-seen fern flowers, naturally, was an indication of magic power. How could it not be? All powers are impotent if not harnessed by humans, yes? So the power of ‘fern flower’ secrecy had to be classed as a power of human invisibility. Used correctly, ferns could confer the power of going unnoticed.

We have the receipt of the fern seed; we walk invisible — Shakespeare

Moonworts (the genus Botrychium) were especially potent in this regard. Like the rest of the ferns, their “flowers” were never observed. But the ephemeral nature of the moonwort plants themselves piqued more interest yet. Most ferns have a long season of conspicuous growth, or they’re evergreen. The above-ground plants of moonworts are tiny, and short-lived. They may appear for a month or two in early summer, then disappear from sight without a trace. And where seen in one year, they may be unseen again for another ten years before popping up unexpectedly. And they are ecologically unpredictable. Their criteria for good habitat seem to be completely different from the preferences of every other kind of plant.

And so, according to moonwort lore, one could tap the power of Botrychium invisibility and go unnoticed on crime sprees. Moonworts, “more beholden to the night“, were complicit in breaking/entering crimes. But only for those who had the botanical skills to know what a moonwort is and where and when to find one. Don’t worry, though, botanists are beholden to the day and are too busy to go thieving in the night. Botanists are more interested in keys for identification than the keys for unlocking doors and the invisibility needed for successful crime. At the end of this post is my draft key to the moonworts of British Columbia (including Botrypus and Sceptridium, which only recently have been commonly segregated from Botrychium). Give it a try (ask me if you don’t know the terminology). Notice how many species appear in this key. A lot.

Why do we have so many moonwort species in North America, whereas very few occur in Eurasia or beyond? Maybe there’s something special about this continent that is lacking elsewhere. Or maybe it’s because moonworts have never been studied anywhere so superbly as by the American taxonomists and moonwort explorers Herb & Florence Wagner:

The Wagners had the good botanical eye (the capability of visual memory, which is key to the work of a plant taxonomist) that could meticulously sort out bewildering variation into sensible classification. Considering the rarity and here-today-gone-tomorrow nature of moonworts, that was not an easy task. The Wagners left us a legacy of taxonomic clarity. Without them, we would still be moonwort-blind. I wish they were alive today so I could ask them whether they agree with me that some of our North American species are present in Eurasia but overlooked by the botanists there. I’ve mentioned those overlooked moonworts to some European botanists, and so far I’ve received only the correspondence equivalent of a blank stare.

I’ve been working intensively since 2016 to document the flora of the Robson Valley. Throughout those years, I’ve been struck by the relative low diversity and abundance of moonworts. So many habitats in the region seem ideal, but there never was much. Maybe I was just searching in the wrong years, when the moonworts were dormant? Or maybe I just wasn’t “blessed” or “mad” enough to see them. It’s hard not to believe in intentional elusiveness of the moonworts. But the 2023 work, exploring the Walker, brought many more species, many of the long expected ones, into the Robson Valley flora. Maybe I was finally blessed. Or maybe Shane brought good luck. And such moonworts that Shane and I found! Like these (B. alaskense, B. boreale, B. echo, B. lanceolatum):

Thank you Shane. And thank you Florence & Herb Wagner. It was great fun moonworting in the Walker!

                  Key to Botrychium sensu lato of British Columbia
1a Trophophores evergreen, trophophore of previous year present ...Sceptridium
  2a Trophophore stalk 15–30 mm; fertile portion of sporophore 1–2 x long as wide, 
  branches spreading; mostly INT ...S. multifidum
  2b Trophophore stalk 30–140 mm; fertile portion of sporophore 2–5 x long as wide, 
  branches steeply ascending; COAST and COL ...S. silaifolium
1b Trophophores all deciduous, relatively delicate, one per plant ...2
  3a Trophophore 3–4 x pinnate, mostly >100 mm wide, green from late spring through 
  summer ...Botrypus
  3b Trophophore 1–2(-3)x pinnate, <<100 mm wide, ephemeral, usually fading after 1-
  2 months ...Botrychium s. str.

                 Key to Botrychium sensu stricto of British Columbia
1a Trophophore modified into a second sporophore, no expanded blades present ...B. paradoxum
1b Trophophore with expanded blades (though sometimes bearing sporangia) ...2
  2a Terminal pinna of trophophore broadly rounded at apex; common stalk of    
  trophophore and sporophore at or near ground level ...B. simplex
  2b Terminal pinna of trophophore truncate or emarginate at apex; common stalk 
  elevating the trophophore-sporophore attachment above ground level ...3
    3a At least proximal pinnae of trophophore pinnatifid or pinnate ...4
      4a Trophophore proximal pinnae as long as the distal portion, hence 
      trophophore more or less deltate or pentagonal in outline ...5
        5a Pinnules more or less ovate to flabellate, touching or even overlapping  
        ...Botrychium boreale
        5b Pinnules more or less narrowly oblanceolate to linear, well spaced ...6
          6a Trophophore dark green, ultimate segments mostly <2 mm wide ...B.   
          lanceolatum subsp. angustisegmentum
          6b Trophophore medium or yellowish green, ultimate segments mostly >2 mm 
          wide ...B. lanceolatum subsp. lanceolatum
      4b Trophophore proximal pinnae distinctly shorter than distal portion, 
      trophophore of narrower shapes, usually more or less ovate in outline ...7
        7a Trophophore proximal pinnae exaggeratedly long, much longer than the 
        second pinnae ...B. michiganense
        7b Trophophore proximal pinnae <, = or slightly > second pinnae ...8
          8a Trophophore conspicuously stalked ...B. pedunculosum
          8b Trophophore sessile or nearly so ...9
            9a Plants glaucous; trophophore pinnae pinnatifid, often shallowly so 
            ...B. hesperium
            9b Plants not glaucous; trophophore pinnae (except depauperate plants) 
            pinnate or deeply pinnatifid ...10
              10a Trophophore veins relatively inconspicuous; pinnules not 
              overlapping, mostly not contiguous, proximal ones of the proximalmost  
              and/or second basiscopic pinnules more widely spreading than the 
              others (thumb-like) ...B. echo
              10b Trophophore veins conspicuous; pinnules mostly contiguous or  
              overlapping, those of all pinnae having about the same orientation 
                11a Trophophore pinnae more or less tapered to the apex; sporophore 
                proximalmost branches often much longer than the adjacent ones, 
                sporophore stalk often so short that the proximalmost branches arise 
                from near the base ...B. alaskense
                11b Trophophore pinnae rounded to the apex; sporophore proximal 
                branches not much longer than the adjacent ones, sporophore stalk 
                consistently elongated ...B. pinnatum
    5b Trophophore 1x pinnate, though some proximal pinnae may be deeply notched 
    downward from the distal margin ...12
      12a Trophophore pinnae more or less square; plants minute, thick, stiff, 
      friable; usually emerging in late summer-autumn ...B. mormo
      12b Trophophore pinnae flabellate, (ob)ovate, elliptic, oblong, spatulate, or 
      suborbicular; plants sometimes leathery or fleshy, but not stiff or friable;  
      usually emerging spring-mid summer ...13
        13a Most or all trophophore pinnae sporangium-bearing along their margins; 
        spores abortive ...B. x watertonense
        13b No or few trophophore pinnae sporangium-bearing, if sporangia present, 
        then only on the basiscopic half proximal pinnae margins; spores mostly well 
        formed ...14
          14a Trophophore pinna apices spanning an angle of 100–220° or more ...15
            15a Trophophore comparatively thin, not leathery, pinnae distal margins 
            consistently crenate and/or erose ...B. crenulatum
            15b Trophophore comparatively thick, leathery, pinnae distal margins 
            entire or slightly and irregularly notched or crenulate ...16
              16a Trophophore pinnae lateral margins separated by an angle of 100- 
              180° ...B. neolunaria
              16b Trophophore pinnae lateral margins separated by an angle of 180-
              220° ...17
                17a Proximal pinnae asymmetric, the basiscopic margin distinctly 
                longer and straighter than the acroscopic margin, often deeply 
                notched (like moose antlers); mature sporophore stalk usually <2x 
                trophophore length ...B. tunux
                17b Proximal pinnae more or less symmetric, the lateral margins 
                roughly equal in length and curvature; mature sporophore stalk 
                usually >2x trophophore length ...B. yaaxudakeit
          14b Trophophore pinnae apices spanning an angle of up to 100° ...18
            18a Trophophore pinnae linear, narrowly oblong or narrowly oblong-
            oblanceolate ...B. lineare
            18b Trophophore pinnae of wider shapes ...19
              19a Trophophore pinna attachment 3–4 mm, basiscopic margin decurrency 
              distinct to the next pinna below; plants glaucous ...B. adnatum
              19b Trophophore pinna attachment <3 mm, basiscopic margin decurrency 
              absent or inconspicuous and usually not reaching the adjacent pinna 
                20a Pinnae strongly ascending; distal margins conspicuously dentate-
                lacerate ...B. ascendens
                20b Pinnae perpendicular to the rachis or weakly ascending; distal 
                margins entire or crenate ...21
                  21a Trophophore incurved proximally and distally, up to 40 x 10 
                  mm, pinnae up to 5 pairs; proximalmost pinnae usually with a deep 
                  central cleft; reported based on a poor specimen, needs 
                  confirmation ...[B. campestre]
                  21b Trophophore flat at least distally, up to 100 x 25 mm, pinnae               
                  up to 10 pairs; pinnae usually entire or with numerous shallow 
                  notches ...22
                    22a Proximal sporophore branches usually 1-pinnate; trophophore 
                    usually stalked; proximalmost pinna pair usually = second pair; 
                    common and widespread ...B. minganense
                    22b Proximal sporophore branches usually 2-pinnate; trophophore 
                    sessile; proximalmost pinna pair usually distinctly > second 
                    pair; rare ...B. spathulatum

So there you have it. Moonworts and magic. Plants for non-linear thinking. And why not leave a bit of room for magic in this world? For the inexplicable. If everything everywhere can be explained, including moonworts, and us, then what fun is life? And why not? The universe is capricious.

Take that, Richard Dawkins!

2 thoughts on “Explorer’s Log: Moonwort Magic

    • Hi Steve, No, the ball-like structures are sporangia, and the sporangia form on the sporophores. The leafier part is the trophophore. The reason for the terminology is that the whole above-ground part of the plant is understood to be a single leaf that is subdivided into fertile (sporophore) and infertile (trophophore) portion. Those those two portions look like a leaf and a stalk with sporangia, they’re actually thought to be specialized portions of a single leaf.

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